1. Field of the Invention
The present invention relates to a method of data transmission, and more particularly to a method of data transmission with a videophone as a terminal and operated with a smart key, which is suitable for transmission with confidential and/or value-added data.
2. Description of the Related Art
A videophone uses H.322, SIP or other common communication protocols to provide a high quality audio-video (AV) data transmission and is currently a developed product. A user with Ethernet and an IP address can utilize the videophone to communicate with another videophone user worldwide, face-to-face. The videophone can be applied to all IP network structures including xDSL (x Digital Subscriber Lin), cable, LAN (Local Area Network) and VPN (Virtual Private Network). Thirty real-time image frames per second can be communicated through the videophones connected to a wideband network, and therefore the applications of remote AV transmission like distance education, remote monitoring and videoconferences can be achieved by videophones. But if the verification of a user, the communication of confidential data or purchase of AV service is required, it is difficult for traditional videophones to meet these requirements.